This invention relates to artificial kidney systems, and more particularly, to a degassing system for supplementary use with or for incorporation in dialysis machines.
In dialysis, a patient's blood and dialysis solution flow through a dialyzer which includes a semipermeable membrane for separating blood and dialysis solution. Impurities from the blood cross the membrane and enter the dialysis solution for disposal.
In some systems the dialysis solution is drawn through the dialyzer under a negative pressure (i.e., below atmospheric pressure) by a dialysis machine. The reduction of pressure on the dialysis solution to below atmospheric pressure allows dissolved gas to come out of solution and form bubbles. If such bubbles enter the dialyzer, they can undesirably impair the efficiency and operation of the dialyzer.
Degassing or deairing systems are known for removing air or other gases from dialysis solution prior to dialysis. Such systems are shown in U.S. Pat. Nos. 3,528,550; 3,598,727; 3,626,670; 3,878,045; and British Patent No. 1,501,956. As used herein, degassing refers to subjecting a liquid to very low negative pressures, such as -600 to -700 mm/Hg, so as to remove both entrained and dissolved gases from a liquid. Deairing refers to a milder treatment where the liquid may be subjected to pressure only as low as perhaps -300 mm/Hg and only visible gas bubbles are removed with little, if any, effect on removal of dissolved gases.
The foregoing patents disclose both (1) complete dialysis machines; and (2) central delivery systems in which the dialysis solution is prepared at a central location and then delivered to multiple remote stations or bedside consoles. In some central delivery systems the dialysis solution is degassed at the central station and the bedside console may include a deairing unit which will remove only visible bubbles. In other systems there is no provision for degassing at the central station, and therefore the liquid entering the console and dialyzer will only be deaired. In such systems it has been found to be desirable to degas liquid received from the central station prior to its delivery to the console.
It is therefore an object of this invention to provide a supplementary system for degassing liquid flowing to a bedside console.
This and other objects of the invention will become apparent from the following description and appended claims.